Tank's appearance is modeled after an actual army tank with his left arm resembling a cannon, and his base being like the treads on an army tank as well. Its' appearance also seems to be more metallic and robotic, despite the fact that Robert was carving a wooden puppet for a majority of the film, and it is never explained why Tank seems to have this appearance and not the apperance of a wooden puppet. Tank contains the soul of its namesake, Robert Winsley after he is killed by Dr. Magrew.